Eye testing device



Y Jvuly`2, 1940. .1.AF. NEUMUELLER UAL I En: msnm nzv'xcl. x i Filed Aug. is; "195s 2 l-ffthetest; t

` Figs. II and III areace 'views of the polariz# setts This invention relates to improved means and method of testing eyes.

One of the principal objects of the invention is to provide novel means and method of testing sight, especially where malingering is suspected.

Another object is to provide means at a suitable distance from the eyes which may be rendered visible to one or the other oi' the eyes separately, or to both eyes simultaneously.

Another object is to provide novel means and method vof shifting the visual stimulus from one eye to the other without the knowledge oi the subject.

Another object is to provide a projector hav ing means associated therewith for projecting an image by means of light rays polarized in a given plane, and to provide means adapted to be associated with the eyes, one of which is polarized in the same plane as the projected image andvfill permit vision oi' the test means. and the'other polarized in a plane substantially normal to the iirst means and which will render' the test means invisible to said eye.

Another object of the invention is to provide an attachment which may be utilized with standard projectors of the type now irl-commercial use.

Another object of the invention is to provide a smooth image receiving screen within the eld cf vision oi the subject upon which the test image may be projected so that the polarized light utilized in producing the test image will not become depolarized.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing and it will be understood that many changes may be made in the arrangement of parts, details of construction and methodshown and described without departing from the spirit of the invention as set forth in the accompanying claims. We. therefore'do not uish to be limited to the exact arrangement ofparts, de-

tails of construction, and method shown and described as the preferred form only has been shown by way of illustration..

i Referring to the drawing: r

Fig. I is a. diagrammatic perspective view i1- lustratingthe meansand method of performing ing means or disks adapted to be placed before the eyes oi the subject during the test;

Fig. IV isa face view of the attachment adaptunitaril STATES Y' l 2,206,303 1:11 an: TESTING navron Julius F. Neumueller, Qninebaug, Conn., rand James Y. Taylor, Southbridge, Mass., assignorl to American Optical Company, Southbridge, Mass., a voluntary association of Massachnj Appiieaosn August 19. 193s, serial No. asses j i 2Claims(CLss-zo ed to be utilized with the projector to polarize the light utilized in producing the tst image;

Fig. V is a sectional view taken on linc V-V of Fig. IV looking in the direction indicated by the arrows.

The device embodying the invention is adapt/ed particularly for use in testing the eyes of individuals suspected oi' malingering or pretending' blindness or partial blindness oi' one or the other of the eyes, as for instance in cases of. individuals claiming compensation ior accidents, exemption from military service, etc., or in any instance where the replies of the subjectas to; his vision cannot be relied upon. It is therefore essential that such tests/.be

made by means or methods whereby the visual 'f acuity oi' each respective eye of the subject may be separately determined without direct knowledge on the part of the subject as to which eye is being tested. n

Several devices have been utilized in the past ior accomplishing this result but such devices have not been wholly practical because it has been difiicult to keep the subject from knowing which eye was being tested. one of the primary objects of this invention to overcome the difiiculties of the prior art and to provide means whereby the eyes of individuals may be tested separately or simultaneously without knowledge on the part of the subject as to N Y which of the eyes is seeing or if both eyes are seeing.

Referring 4more particularly to the drawing wherein like characters, of reference designate like parts throughout the several views, the de- 8S vice embodying the invention comprises, as shown in Figs. I, IV and V, a polarizing unit l in the means of which the disk l may be rotated to alter theaxls or the polarizing material. The u nger wheel 8 is plvotally attached at 9 within 4,the slide 2 and is provided with a curved slot Il through which a stop pin III mounted in the It is, therefore, B l

'Ihe polarizing unit l is adapted to be mounted within a suitable support in a projectingapparatus which, as shown diagrammatically in Fig.

usual type. The projector is provided with the usual slide bearingA the means I6 for producing the projected test image I1. This projected image is focused on a suitable receiving screen l "I la supported wltnmthe. direct nele' of vision or the eyes |B and 2D of the subject being examined or testedr l Suitable polarizing disks 2| and-Hare lplaced before the eyes of the subject. These polariz- A l0 ingrdisks are adapted to be supported by a trial frame or other means known in the art.

The polarizing disk 22 positioned before the eye 2U has its axis of polarization extending ver tically, while the polarizing disk 42| before the 18Y eye i9 has its polarlzlng axis extending horizon- It is to be understood that if desired the axes of the disks 2| and 22 may be shifted, care being taken that the respective axes are at ninety de- 20 grees or perpendicular to each other.l

- Referring more particularly to Fig. I, it will be noted that the axis of polarization of the disk 4, which controls the polarization o f the projected image extends vertically, and -iri this particular instance the image would be visible only to the eye 20 becausethe axis of polarization of the disk 22 before the eye 20 is parallel to the axis of the reflected vlight of the projected image, the axis of polarization of the disk 2| B0 being substantially normal to the reflected plane of the test image' Il and rendering said image invisible to the eye I9. To bring about a reverse condition, wherein the image Il will be visible only to the eye I9, the nger wheel 8 is rotated until the axis of polarization of the light prod ucing the image il is substantially parallel n-ith the axis of the polarization of the disk 2| before the eye I9. At the same time this movement causes the axis of polarization producing the image |1 to lie in a plane 'substantially normal to the axis of the polarizing means 22 before the other eye. Thus the visibility of the image Il will be shifted from lone eye to the other. This shift will take place Without the knowledge of u the subject and without in any way disturbing The test image |`l-may be rendered visible to both eyes simultaneously by rotating the axis ofpolarization of the disk 4 to' an axis of about n forty-five degrees, which will permit enough light to pass through the polarizing disks 2| and 22 to enable the subject to see the test image I1 with both eyes. v'I'he axes of polarization of the disks 2| and 5g 22 are indicated by suitable markings 23 and 24 placed on the disks. 5; a

Instead of utilizing afsingle test member 1, it is to be understood that suitable reading matter may be' projected or imaged on the receiving .o screen I8'. In this instance the subject under test would be asked to read the projected matter and during the reading the operator may shift the axis of polarization of the disk 4 so as to change the visibility of the reading matter from 65 one eye to the other. .This change is imperceptible to the subject, and in this way an accurate test of the eyes may be obtained. If there I is no hesitation on the part of 4the subject iu reading when this shift, or change of polarization, takes pla-ce the operator will know that the subject is seeing with both eyes as otherwise he could not continue to read.

This shifting of the polarization of the proi jeeted test means is brought about by the mere Tl turning ofnthe finger wheel 8. andcan be acmonlyusedin the art,untilthebestvisual acuity I is attained.

The polarizing means -referred to throughout the specification bas being formed of sheet material' having a plurality of minute crystals oriented therein, is preferablylformed ofa transparent 1o Y supporting medium in `which the -crystals, are placed when the medium is in plastic or liquid state. 'Ihe crystals are oriented and are held n in said oriented relation until the material hard- During the orientlng of the crystals, the 1| material is made into sheet form and is allowed to harden in this form and may thereafter be cut into the size and shape desired.

From the foregoing description it will be seen that simpleeicient and economical means and method have been provided for accomplishing all the objects and advantages of the invention, particularly that of producing malingering test means which may be quickly and easily manipulated. Y Having described our invention we claim:

1. Eye testing apparatus for testing the ey of an individual complising the combination of a viewing screen positioned within the field of vision of the eyes under test, light projection n means fol projecting a beam of light on said viewing screen, a slide having image forming means thereon in said projection means with the image forming means in alignment with the projected beam of light for producing a single test image u on said viewing screen, light polarizing means rotatably supported in the path of the projected light of said projection means movable to a position for polarizing the light Vproducing the test image in a given direction, and movable to a 4' Second position for polarizing the light produc ing the test image in a direction substantially normal to the first direction while continuously projecting said image, polarizing means positioned before each of the respective eyes through which the light rays from the projected test image must pass so as to be visible to the respecaxis of the polarized light producing the test 4 image when in said second position of adjustment, and means for shifting the axis of polaris@ zation of the iight producing the test image from L" an initialposition substantially parallel with the axis of polarization of the polarizing means be-` fore one eye to a position substantially parallel with the axis of polarization of the polarizing means before the other eye whereby vision o( said test image maybe gradually Ashifted from one eye to the other with the individual under test having no direct knowledge of said shifting.

2. The method of testing the eyes of an in- J0 dividual comprising projecting a beam of light ing screen, rotatably supporting light polarizing meansin' the path of the projected light for.

polarizing the light producing t'ne test image in a given direction, rotating said polarizing means 'to a second position for polarizing the light producing the test image in a direction substantially normal to the nrst while continually projecting said image, positioning polarizing means before Veach of the respective eyes through which the light rays from the projected test image must pass so as tc be visible to therespec'tive eyes and controlling tLe position of the axes of polarif zation of said polarizing means'so that the axis of one of saidv polarizing means will be located substantially parallel *.xdth the airis of polarization of the light producing the test image when the polarized light producing said image is in one position of adjustment and so that the other tialy nonna! to the axis of polarization .oi the polarizing means-.-,beiore the rst eye and substantially parallel with the axis of the polarized light prcducing the test'image when in salu second position of` adjustment and shifting the axis ofvpolarization of lthe light producing the test image from an initial position substantially' parallel with the axis of polarization of the pol arizing means before one eye to a position substantialy parallel with the axis of polarization of the polarizing means before the'other eye whereby vision of said test image may be gradually shifted from one eye to the other with the individual under test having no direct knowledge JULIUS F. NEUlifUELLm. JAMES Y. TAYLOR.

of said polarizing means will have its axis of i' polarization positioned in a direction substan- 

